1. Field of the Invention
The present invention relates to a cooling apparatus for a vehicular engine, and in particular to cooling technology for an automobile engine which incorporates at least one of an exhaust gas recirculation unit and an intercooler.
2. Description of the Related Art
With an automobile engine, there are those where an EGR (Exhaust Gas Recirculation) unit is provided for reintroducing a part of the exhaust gas back into the engine to thereby reduce the NOx in the exhaust gas, and those where an intercooler is provided between the turbo charger and the intake manifold for cooling the intake and exhaust gas. Since the EGR and intercooler are each exposed to high temperature exhaust gas, a liquid cooling system is employed where a coolant is circulated by the engine pump, and the heat from the intercooler and the EGR is carried to the radiator, to thereby to cool the intercooler and the EGR.
With the above, since the engine pump is used in the cooling of the EGR and the intercooler, when the engine stops, then the engine pump also inevitably stops. In this case, the temperature of the EGR and the intercooler increases, and hence immediately after stopping, the coolant therein boils and the metal parts are exposed to high temperature, with the result that there is a reduction in life.